EP0201636B1 - Rauschlöschvorrichtung für stimulierbares Phosphorblatt - Google Patents

Rauschlöschvorrichtung für stimulierbares Phosphorblatt Download PDF

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Publication number
EP0201636B1
EP0201636B1 EP85302966A EP85302966A EP0201636B1 EP 0201636 B1 EP0201636 B1 EP 0201636B1 EP 85302966 A EP85302966 A EP 85302966A EP 85302966 A EP85302966 A EP 85302966A EP 0201636 B1 EP0201636 B1 EP 0201636B1
Authority
EP
European Patent Office
Prior art keywords
lamp
stimulable phosphor
current
power
phosphor sheet
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP85302966A
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English (en)
French (fr)
Other versions
EP0201636A1 (de
Inventor
Shigemi C/O Patent Division Fujiwara
Katsuhide C/O Patent Division Koyama
Hiroshi C/O Patent Division Kageyama
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Toshiba Corp
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Toshiba Corp
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Publication date
Application filed by Toshiba Corp filed Critical Toshiba Corp
Priority to DE8585302966T priority Critical patent/DE3572874D1/de
Publication of EP0201636A1 publication Critical patent/EP0201636A1/de
Application granted granted Critical
Publication of EP0201636B1 publication Critical patent/EP0201636B1/de
Expired legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
    • G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
    • G01T1/02—Dosimeters
    • G01T1/10—Luminescent dosimeters
    • G01T1/11—Thermo-luminescent dosimeters
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
    • G03C5/00—Photographic processes or agents therefor; Regeneration of such processing agents
    • G03C5/16—X-ray, infrared, or ultraviolet ray processes

Definitions

  • the present invention relates to noise erasing apparatus for use with stimulable phosphor sheets.
  • U.S. Patent No. 3859527 entitled Apparatus and Method for Producing Images Corresponding to Patterns of High Energy Radiation, disclosed and claims a method of radiation image recording which employs a radiation image storage panel comprising a stimulable phosphor which emits light when stimulated by electromagnetic waves selected from visible light and infra-red after exposure to radiation, such as X-rays, a-rays, (3- rays, high energy neutrons, electron beams, vacuum ultra-violet rays, ultra-violet rays, and other similar electromagnetic waves or corpuscular beams.
  • electromagnetic waves selected from visible light and infra-red after exposure to radiation
  • electromagnetic waves selected from visible light and infra-red after exposure to radiation
  • electromagnetic waves selected from visible light and infra-red after exposure to radiation, such as X-rays, a-rays, (3- rays, high energy neutrons, electron beams, vacuum ultra-violet rays, ultra-violet ray
  • U.S. Patent No. 4236078 entitled Method and Apparatus for Recording and Reproducing a Radiation Image, describes a method in which the final visible image may be reproduced in the form of a hard copy or may be displayed on a cathode ray tube.
  • the stimulable phosphor sheet used in this method may take various forms, such as a panel, a drum, or the like, which are herein generally referred to as imaging plates (IP).
  • IP imaging plates
  • the radiation energy of the radiation image stored in the stimulable phosphor sheet should disappear when the sheet is scanned with a simulating ray of a sufficient intensity to sequentially release the radiation energy stored as light emission.
  • the stored radiation energy cannot be completely eliminated simply by scanning by the stimulating ray.
  • a first erasing in which the radiation image previously stored in the stimulable phosphor is erased at high illumination for a long period of time by use of a large-scale device, can be carried out before the stimulable phosphor sheet is used in radiography.
  • a stimulable phosphor contains a trace of radioactive isotopes, such as 226 Ra and 4 °K, which emit radiations and cause the stimulable phosphor sheet to store the emitted radiation energy, even when the sheet is not being used in radiography. These traces of radioactive isotopes also constitute a cause of the noise developing in the reproduced visible radiation image. Further, a stimulable phosphor sheet is also affected by environmental radiations, such as cosmic rays and X-rays emitted from other X-ray sources and it stores the energy thereof. These types of radiation energy also cause noise to appear in the visible radiation image reproduced therefrom. In order to erase this obstructive radiation energy, a second erasing by a small scale erasing device can be conducted over a short period of time immediately before the phosphor sheet is re-used.
  • radioactive isotopes such as 226 Ra and 4 °K
  • the illuminant may be, for example, a tungsten-filament, fluorescent, sodium, xenon, or iodine lamp.
  • the illumination depends on the luminance of the lamp used in such a device, and the cause of noise, as described previously, and temperature radiation increases with a decrease in the color temperature of the illuminant. Further, the luminance and the color temperature of the lamp are determined in accordance with the load power to the lamp.
  • the load power (P,) is given below as:
  • an X-ray diagnostic system 20 having a taking-up and feeding device 22 for unexposed stimulable phosphor sheets 10, a noise erasing apparatus 24, a transport system 26, a light-tight portion 28, and a receiving device 30 for exposed stimulable phosphor sheets 10 transported by the transport system 26.
  • the taking-up and feeding device 22 comprises a supply magazine 32 to be removed from the taking-up and feeding device 22, to enable convenient loading of unexposed stimulable phosphor sheets 10, (hereinafter referred to as IP), in a darkroom, a taking-up mechanism 42 including take-up pads 34, 36 for taking up the IPs one by one from the supply magazine 32 by suction generated by vacuum pumps 38, 40, and carrying rollers 44 for forwarding an unexposed IP 10 to the transport channel of the transport system 26.
  • IPs are lifted up one at a time by the take-up pads 34, 36 which act on the opposite side of the IP to the fluorescent layer.
  • the noise erasing apparatus 24 comprises a lamp 46, for example, a tungsten-filament, fluorescent, sodium, xenon, or iodine lamp, and a reflector 48, disposed as shown in Figure 1, so that each IP 10 is exposed uniformly to the light from the lamp 46.
  • the noise erasing apparatus 24 is synchronised with the movement of the IP 10 so that it emits light when the forward end of the take-up IP 10 reaches the carrying rollers 44.
  • the IP 10 is exposed to the light when it is passed over the noise erasing apparatus 24 at a predetermined speed by the carrying rollers 44.
  • a transport system 26 is provided in the X-ray diagnostic 20. During an operating cycle, the transport system 26 concurrently transports an unexposed IP 10 from the supply magazine 32 to a pre-exposure station 50, in part defined by the X-ray tube, and an exposed IP 10 from the pre-exposure station 50 to the receiving device 30.
  • the transport system 26 has two continuous band portions 26a, 26b. One portion 26a is occupied in transporting the IP 10 from the carrying roller 44 to the light-tight portion 28, the other 26b is occupied in transporting the IP 10 from the light-tight portion 28 through the pre-exposure station 50 to the receiving device 30.
  • Each portion 26a, 26b includes a pair of continuous band loops 52a, 54a and 52b, 54b, which run around roller wheels in a path.
  • the IP 10 is transported in the transport channel defined by these band loops 52a, 54a and 52b, 54b while being held between the two facing bands loops 52a, 54a or 52b, 54b.
  • the IP 10 is transported by the transport system 26 and stopped at the position where the IP contacts the position detector 56 disposed in the forward end thereof. The IP 10 stays at this staying position during a predetermined period without being transported to the second portion 26b of the transport system 26 :
  • a guide plate 58 for the IP 10 there are a guide plate 58 for the IP 10, a light-sealed roller 60 for forwarding the IP with the guide plate 58, and a defect detector 62 for detecting a defect on the surface of IP 10 by suitable means. These components are arranged to prevent light from entering into the darkroom.
  • the second portion 26b of the transport system 26 includes a top 54b and a bottom 52b band loop which can be moved in the direction perpendicular to the path of the band loops, and into the exposure position where the X-ray beam from the source (not shown) passes through a patient positioned adjacent thereto. Movement of the IP 10 into the exposure position is carried out after the IP 10 is advanced in the precise position on the band loops 52b, 54b, for example, central portion of the second transport portion 26b. If the defective IP 10 is found by the defect detector 62, it will be transported directly to the receiving device 30 without being moved into the exposure position.
  • the receiving device 30 comprises a timing belt 64 riding on the timing belt pulleys for depositing the exposed IP 10 in the receiving magazine 66 by gripping it in combination with a drive roll 68, a pair of ejector rolls 70 are provided for feeding the exposed IP 10 into the receiving magazine 66.
  • This magazine is mounted on tracks (not shown) to facilitate its removal to a darkroom for loading and unloading.
  • a spring-biased press pad 72 is arranged downstream of the ejector rolls 70 in the feeding path. This press pad 72 is pivotable about an axis and springs urge the pad perpendicularly to the direction of movement of the IP.
  • the pad is flapped by suitable driving mechanism 74 to load the exposed IPs uniformly in the receiving magazine 66.
  • a bar-code reader 76 is provided for reading the identification of the IP 10 and providing electrical signals corresponding to it.
  • the magazine 66 is in a light-tight enclosure.
  • the lamp 46 is connected to the AC power source 102 through a power line 104.
  • a current detector means 106 is connected to the power line 104 and it detects the lamp current i(t). The detector calculates the effective value I e of the current i(t). The detector output is connected to one of the input terminals of a comparator 108 which is also provided with a reference value I r on its other input terminal.
  • a power controller 110 is connected to the output terminal of the comparator 108 and it controls the current i(t) passing through the power line 104, in accordance with the output of the comparator 108, so that the AC power supply to the lamp 46 from the source 102 is maintained at a constant value.
  • the effective value l e may be calculated in the current detector 106 from the detected current i(t) as where T is the period of the alternating current.
  • the difference I d between the reference I r and the effective value 1. of the detected current i(t) is supplied to the power controller 110.
  • the reference value I r is determined relative to the constant value of the load power in the lamp to be maintained.
  • the power controller 110 is the phased controlled type suitable to be interposed between the AC power source 102 and the lamp 49 and comprises a triac 112 connected to the power line 104.
  • a bias circuit (not shown) provides a rectified sample which is applied to the gate of triac 112.
  • triac 112 Upon the result of the comparator, triac 112 will conduct, varying the interval of the rectified sample signal for phase controlling the current i(t) through the power line 104. Thereby, it can be performed to maintain the load power of the lamp 46 at constant value during a controlling period within very close limits.
  • an alternating current power source is used in the erasing apparatus as a power source.
  • the lamp has a resistance which varies with the variation of the filament temperature.
  • the resistance R has a great effect on the lamp current I e , and, if we assume that the variation of the lamp resistance R, in accordance with the variation of the filament temperature can be ignored during the operation within the regulated power supplies, a load power P, in the lamp 46 is represented by the following equation: where E, is the lamp voltage.
  • the operation for maintaining the load power at constant value is performed by using the effective value I e , operationally 1 e 2 , where
  • the load power in the lamp 46 is kept at a constant value despite changes in the source voltage.
  • the embodiment utilises the power controller of the phased controlled type, however, it is possible to utilise suitable current control means by varying the voltage. Further, it is not limited to the use of a triac in the power controller 110 of the phased controlled type, and can be thought to use other equivalent components instead of a triac.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Molecular Biology (AREA)
  • Health & Medical Sciences (AREA)
  • Radiography Using Non-Light Waves (AREA)
  • Apparatus For Radiation Diagnosis (AREA)
  • Supply And Distribution Of Alternating Current (AREA)
  • Control Of Voltage And Current In General (AREA)
  • Control Of Electrical Variables (AREA)
  • Light Sources And Details Of Projection-Printing Devices (AREA)

Claims (4)

1. Störungslöscheinrichtung zur Verwendung bei einem stimulierbaren Phosphorbogen, mit einer Quelle für Wechselstrom (102); einer Lampe (46) zur Ausstrahlung von Störungen löschendem Licht mit einem vorbestimmten konstanten Luminanzwert und einer vorbestimmten Farbtemperatur; wobei die Lampe mit der Quelle über eine Versorgungsleitung (104) und eine Leistungssteuereinrichtung (110) verbunden ist, gekennzeichnet durch eine Stromdetektoreinrichtung (106), die an die Leitung angeschlossen ist und Strom feststellt, der durch die Lampe fließt,-und einen Effektivwert des Stromes berechnet, eine Vergleichseinrichtung (108) zur Erzeugung eines Steuersignals für die Steuereinrichtung auf der Grundlage eines Vergleichs zwischen dem genannten Effektivwert des Stromes und einem vorbestimmten konstanten Wert, so daß die der Lampe durch die Steuereinrichtung zugeführte Leistung die Ausstrahlung von Störungen löschendem Licht bei dem vorbestimmten Luminanzwert und der vorbestimmten Farbtemperatur bewirkt.
2. Störungslöscheinrichtung nach Anspruch 1, dadurch gekennzeichnet, daß die Leistungssteuereinrichtung vom Phasensteuerungstyp ist, um so den durch die Leitung fließenden Strom zu steuern.
3. Störungslöscheinrichtung nach Anspruch 2, dadurch gekennzeichnet, daß die Leistungssteuerungseinrichtung einen Triac zur Änderung der Periode der gleichgerichteten Probe ist, die dessen Gatter zugeführt ist.
4. Störungslöscheinrichtung nach Anspruch 1, dadurch gekennzeichnet, daß die Bestrahlungsmittel eine Beleuchtungsquelle (46) sind, die in einer Transporteinrichtung zum Transport des stimulierbaren Phosphorbogens (10) in Förderrichtung hinter einem Speisemagazin zum Stapein einer Anzahl von stimulierbaren Phosphorbögen darin angeordnet ist.
EP85302966A 1984-04-19 1985-04-26 Rauschlöschvorrichtung für stimulierbares Phosphorblatt Expired EP0201636B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE8585302966T DE3572874D1 (en) 1985-04-26 1985-04-26 Noise erasing apparatus for stimulable phosphor sheet

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP59079979A JPH0763463B2 (ja) 1984-04-19 1984-04-19 放射線診断装置

Publications (2)

Publication Number Publication Date
EP0201636A1 EP0201636A1 (de) 1986-11-20
EP0201636B1 true EP0201636B1 (de) 1989-09-06

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ID=13705439

Family Applications (1)

Application Number Title Priority Date Filing Date
EP85302966A Expired EP0201636B1 (de) 1984-04-19 1985-04-26 Rauschlöschvorrichtung für stimulierbares Phosphorblatt

Country Status (4)

Country Link
US (1) US4703178A (de)
EP (1) EP0201636B1 (de)
JP (1) JPH0763463B2 (de)
KR (1) KR890004721B1 (de)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2866264B2 (ja) * 1991-10-25 1999-03-08 富士写真フイルム株式会社 残留放射線画像消去方法および装置

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA938667A (en) * 1971-10-14 1973-12-18 Szabo John Network for varying current through a load
JPS524347A (en) * 1975-06-24 1977-01-13 Fukushiyoku Shiyuu Hexahedron counting and building blocks
US4271387A (en) * 1978-04-20 1981-06-02 Tokyo Shibaura Denki Kabushiki Kaisha Method and system of controlling effective value of alternating current
JPS5561709U (de) * 1978-10-18 1980-04-26
JPS5679310A (en) * 1979-12-03 1981-06-29 Ricoh Co Ltd Load electric power stabilizer
JPS57119300A (en) * 1981-01-16 1982-07-24 Fuji Photo Film Co Ltd Noise eliminator for accumulative phosphor sheet
JPS6043233B2 (ja) * 1981-03-20 1985-09-27 株式会社電元社製作所 抵抗溶接機における溶接電流波形制御方法及びその装置
JPS57204439A (en) * 1981-06-12 1982-12-15 Hitachi Ltd Electric power supplying device
JPH0345404A (ja) * 1989-07-14 1991-02-27 James K Kaimikawa 摩耗表示器を内蔵したゴム製タイヤ

Also Published As

Publication number Publication date
JPH0763463B2 (ja) 1995-07-12
EP0201636A1 (de) 1986-11-20
JPS60222912A (ja) 1985-11-07
KR890004721B1 (ko) 1989-11-25
US4703178A (en) 1987-10-27
KR850007490A (ko) 1985-12-04

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